Total bridges
489
Public highway bridges in Black Hawk County
County profile · official public datasets
Black Hawk County, IA
489 public highway bridges tracked in the FHWA National Bridge Inventory: 52.8% rated Good, 40.7% Fair, 6.5% Poor.
- 489
- Public bridges
- 52.8%
- Good condition
- 6.5%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Black Hawk County posts a top-10% lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 8%
- lowest Poor share in state
- 6.5%
- Poor-condition share
- 489
- public highway bridges
- 1983
- avg year built
Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.
Black Hawk County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Black Hawk County ranks #8 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.5%). Black Hawk County, Iowa contains 489 public highway bridges. Roughly 52.8% are rated “Good,” 40.7% “Fair,” and 6.5% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.
Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.
Source: FHWA National Bridge Inventory. See methodology for full definitions.
Good condition
52.8%
258 of 489 rated 7-9
Fair condition
40.7%
199 of 489 rated 5-6
Poor condition
6.5%
32 of 489 rated 4 or below
In-state Poor-share rank
#8 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 489 NBI-tracked bridges by lowest applicable component rating.
Good 52.8% (258)
Fair 40.7% (199)
Poor 6.5% (32)
Black Hawk County's Poor-condition bridges carry 34,702 vehicle crossings a day
That is 2.2% of the county's reported daily bridge traffic on 6.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,084 crossings a day against 3,129 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.
Computed over the 488 of 489 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
29% of Black Hawk County's bridges have passed the 50-year mark
142 of the 489 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 52.8% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.
Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.
One structure carries 24.2% of the county's Poor-condition bridge traffic
E RIDGEWAY AVE over DRY RUN CREEK, built 1950, carries 8,392 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 32-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 34,702 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Black Hawk County's bridges were built
489 bridges with a recorded construction year, grouped by decade
- 1900s 8
1900–1909
8 bridges
- 1920s 4
1920–1929
4 bridges
- 1930s 5
1930–1939
5 bridges
- 1940s 20
1940–1949
20 bridges
- 1950s 38
1950–1959
38 bridges
- 1960s 39
1960–1969
39 bridges
- 1970s 45
1970–1979
45 bridges
- 1980s
1980–1989
122 bridges
- 1990s
1990–1999
92 bridges
- 2000s
2000–2009
67 bridges
- 2010s 37
2010–2019
37 bridges
- 2020s 12
2020–2029
12 bridges
What this shows Construction peaked in the 1980s, when 122 of the county's bridges still in the inventory were built, which is 24.9% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).
How Black Hawk County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Black Hawk County in number of bridges, with their condition splits. Its 6.5% Poor share is the 4th-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1983 is in line with the group.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Polk County | 545 | 57.8% | 35.8% | 6.4% | 1986 |
| Linn County | 506 | 46.4% | 47.2% | 6.3% | 1987 |
| Black Hawk County (this page) | 489 | 52.8% | 40.7% | 6.5% | 1983 |
| Woodbury County | 455 | 39.3% | 39.6% | 21.1% | 1985 |
| Sioux County | 449 | 62.4% | 34.7% | 2.9% | 1982 |
| Plymouth County | 432 | 52.1% | 26.4% | 21.5% | 1974 |
Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Black Hawk County's. Source: FHWA National Bridge Inventory, 2024 release.
Nationwide counties with similar inventory size or average build year
Two NBI-derived peer sets for Black Hawk County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (489 bridges here).
- Suffolk County, MA · 489 bridges
- Shasta County, CA · 492 bridges
- Lyon County, KS · 492 bridges
- St. Clair County, IL · 486 bridges
Similar average build year
Nearest mean year-built outside IA (1983 here).
- Dallas County, TX · avg 1983 · 3,230 bridges
- Bexar County, TX · avg 1983 · 2,342 bridges
- Sedgwick County, KS · avg 1983 · 1,333 bridges
- Will County, IL · avg 1983 · 649 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (199)
HUDSON RD
FairOver: DRAINAGE DITCH
000000000, Black Hawk, IA
Built 1978 Load: 37.0 t ADT: 4,985
5TH ST
FairOver: CEDAR RIVER
CITY BRIDGE NO. 8, Black Hawk, IA
Built 1967 Load: 37.3 t ADT: 7,280
E 4TH ST
FairOver: VIRDEN CREEK
CITY CULVERT NO. 38C, Black Hawk, IA
Built 1970 Load: 37.3 t ADT: 2,679
US 20 EB IA 27 SB
FairOver: IANR RR TX ST CEDAR RVR
0.4 MI. S OF JCT. 20, Black Hawk, IA
Built 1983 Load: 37.3 t ADT: 10,200
W.4TH ST
FairOver: DRAINAGE
CITY CULVERT NO. 35C, Black Hawk, IA
Built 1986 Load: 37.6 t ADT: 5,322
SB US 218
FairOver: NB US 63
3.6 mi. N of US 20, Black Hawk, IA
Built 1991 Load: 37.6 t ADT: 10,100
IA 21
FairOver: US 20
AT JCT. US 20, Black Hawk, IA
Built 1983 Load: 37.6 t ADT: 7,700
WAGNER RD
FairOver: NO NAME CREEK
CITY CULVERT NO. 16C, Black Hawk, IA
Built 1988 Load: 37.8 t ADT: 415
E.ORANGE RD
FairOver: SINK CREEK
CITY CULVERT NO. 45C, Black Hawk, IA
Built 1988 Load: 38.0 t ADT: 2,777
S CANFIELD RD
FairOver: TRIB TO CEDAR RIVER
88-11-32-02-10, Black Hawk, IA
Built 2004 Load: 38.2 t ADT: 599
SB RP I-380 &20
FairOver: I-380 & 20
AT EAST JCT. I-380, Black Hawk, IA
Built 1980 Load: 38.2 t ADT: 80
EB 20
FairOver: US 218
AT W. JCT. I-380, Black Hawk, IA
Built 1983 Load: 38.6 t ADT: 10,300
E CONGER ST
FairOver: CEDAR RIVER
CITY BRIDGE NO. 13, Black Hawk, IA
Built 1977 Load: 38.8 t ADT: 10,190
E TAMA RD
FairOver: TRIB TO WOLF CREEK
87-12-34-01-10, Black Hawk, IA
Built 2003 Load: 39.2 t ADT: 570
CENTER ST
FairOver: CEDAR RIVER
000000000, Black Hawk, IA
Built 1988 Load: 39.5 t ADT: 5,414
NB US 218
FairOver: BLACK HAWK CK & RD
0.2 mi. N of Jct. U.S. 63, Black Hawk, IA
Built 1991 Load: 39.5 t ADT: 11,250
SB US 218
FairOver: BLACK HAWK CK & RD
0.2 mi. N of Jct. U.S. 63, Black Hawk, IA
Built 1991 Load: 39.5 t ADT: 11,100
HUDSON RD
FairOver: DRY RUN CREEK
000000000, Black Hawk, IA
Built 1969 Load: 40.0 t ADT: 6,993
SB US 63
FairOver: CEDAR RIVER
0.2 mi. N of Jct. US 218, Black Hawk, IA
Built 1970 Load: 40.2 t ADT: 4,550
EB US 20
FairOver: HESS RD
0.3 mi W of W jct 380/218, Black Hawk, IA
Built 1983 Load: 41.5 t ADT: 11,550
HESS ROAD
FairOver: DRAINAGE
CITY CULVERT NO. 54C, Black Hawk, IA
Built 1992 Load: 42.2 t ADT: 4,635
W 4TH ST
FairOver: US 20
0.5 MI. E OF JCT. US 63, Black Hawk, IA
Built 1984 Load: 42.4 t ADT: 2,670
US 218
FairOver: CEDAR RVR & TRAIL
2.9 MI. S JCT. IA #57, Black Hawk, IA
Built 1989 Load: 42.4 t ADT: 21,500
CEDAR HTS DR
FairOver: DRAINAGE
000000000, Black Hawk, IA
Built 1983 Load: 43.3 t ADT: 5,495
W 4TH ST
FairOver: CEDAR RIVER
CITY BRIDGE NO. 34, Black Hawk, IA
Built 1975 Load: 43.7 t ADT: 1,908
US 20 EB
FairOver: IA 58
At the Jct. Iowa #27 & 58, Black Hawk, IA
Built 1984 Load: 43.7 t ADT: 7,050
I 380 SB
FairOver: ELK RUN CREEK & RD
1.9 MI. S OF S JCT US 218, Black Hawk, IA
Built 1983 Load: 44.1 t ADT: 16,600
MITCHELL AVE
FairOver: DRY RUN CREEK
CITY BRIDGE NO. 5, Black Hawk, IA
Built 1980 Load: 44.3 t ADT: 3,127
IA 281
FairOver: WAPSIPINICON RIVER
2.2 MI. E OF S.R. C57, Black Hawk, IA
Built 1989 Load: 44.5 t ADT: 1,240
NB I-380
FairOver: SPRING CREEK
1.6 Mi. N OF Jct. SR V65, Black Hawk, IA
Built 1984 Load: 44.9 t ADT: 8,550
SB I-380
FairOver: SPRING CREEK
1.6 Mi. N OF Jct. SR V65, Black Hawk, IA
Built 1984 Load: 44.9 t ADT: 8,550
MILLER CREEK RD
FairOver: TRIB TO MILLER CREEK
87-12-04-01-10, Black Hawk, IA
Built 1986 Load: 45.4 t ADT: 49
DYSART RD
FairOver: TRIB TO MILLER CREEK
87-12-07-02-10, Black Hawk, IA
Built 1994 Load: 45.4 t ADT: 1,660
W EAGLE RD
FairOver: ROCK CREEK
87-14-24-01-10, Black Hawk, IA
Built 2005 Load: 45.4 t ADT: 471
WINSLOW RD
FairOver: WEST FORK CEDAR RIVER
90-14-09-03, Black Hawk, IA
Built 2008 Load: 45.6 t ADT: 678
US 218
FairOver: QUARRY LAKE & WYTH RD
2.5 Mi. S of Jct. Ia. #57, Black Hawk, IA
Built 1989 Load: 45.7 t ADT: 29,000
IA 21
FairOver: STREAM
3.1 MI. S OF JCT. SR D35, Black Hawk, IA
Built 1959 Load: 46.0 t ADT: 2,480
BROADWAY ST
FairOver: SMALL STREAM
CITY CULVERT NO. 22C, Black Hawk, IA
Built 1974 Load: 46.7 t ADT: 3,506
6TH ST.
FairOver: CEDAR RIVER
CITY BRIDGE NO. 43, Black Hawk, IA
Built 1984 Load: 46.9 t ADT: 5,195
HEARST RD
FairOver: TRIB TO DRY RUN CREEK
89-14-33-02-10, Black Hawk, IA
Built 1978 Load: 47.1 t ADT: 33
DYSART RD
FairOver: TRIB TO MILLER CREEK
87-12-06-02-10, Black Hawk, IA
Built 1994 Load: 48.2 t ADT: 1,660
I 380 NB
FairOver: IANR RR & TEXAS ST
0.3 MI. S. OF JCT. US 218, Black Hawk, IA
Built 1983 Load: 48.2 t ADT: 8,800
W TAMA RD
FairOver: ROCK CREEK
87-14-35-01-10, Black Hawk, IA
Built 2003 Load: 49.9 t ADT: 560
E MARQUIS RD
FairOver: CRANE CREEK
90-12-03-01-10, Black Hawk, IA
Built 2003 Load: 52.5 t ADT: 49
S CANFIELD RD
FairOver: INDIAN CREEK
88-11-17-02-10, Black Hawk, IA
Built 2003 Load: 52.9 t ADT: 678
POYNER RD
FairOver: SPRING CREEK
88-11-25-01-10, Black Hawk, IA
Built 1990 Load: 52.9 t ADT: 33
US 218
FairOver: BROADWAY ST
1.3 MI S of Jct. IA 57, Black Hawk, IA
Built 1989 Load: 55.3 t ADT: 23,100
US 218
FairOver: AIRPORT BLVD
1.1 miles S of jct. IA 27, Black Hawk, IA
Built 1989 Load: 56.5 t ADT: 23,100
I 380 SB
FairOver: SAN MARNAN DR
1.0 MI. N of N Jct. 20, Black Hawk, IA
Built 1983 Load: 56.6 t ADT: 9,050
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.